Processor for photographic paper



April 13, 1965 P. H. STEWART PROCESSOR FOR PHOTOGRAPHIC PAPER Filed Oct.26, 1961 Fig.

PAUL H. STEWART INVENTOR. 5 wa/m QM 7 ATTORNEYS Fig. 4

United States Patent 3,177,793 PRUCESSOR FOR PHOTOGRAPHIC PAPER Paul H.Stewart, Rochester, N.Y., assignor to- Eastman Kodak Company, Rochester,N.Y., a corporation of New Jersey Filed Oct. 26, 1961, Ser. No. 147,39911 Claims. (Cl. 95-94) This invention relates to apparatus forprocessing photographic paper of the type which is developable upon theapplication of heat in a moist atmosphere.

Photographic papers of the type involved have been introduced relativelyrecently and are especially well fitted for use in conjunction withoscillograph recorders. As described in an article on pages 113 and 114of the publication Photographic Science and Engineering, volume 5, No.2, March-April 1961, of which article applicant was one of theco-authors, such papers contain all the chemicals necessary fordevelopment of a latent image therein. This article also shows anddescribes one type of processing apparatus which may be used to developthe exposed paper and wherein the paper is drawn over a heated plateforming one wall of a substantially closed chamber, the chamber beingarranged to retain the vapors driven out of the paper by the heat so asto preserve the desired moist atmosphere without requiring a separatesource of moisture. Other arrangements for preventing the moisture orvapor from being dissipated have also been proposed, such as by the useof a nonpermeable belt overlying the paper throughout its movementthrough the processing apparatus. However, while such apparatusesproduce most satisfactory developing action, they are relatively bulky,complicated in construction, and inconvenient to use. Moreover the paperbeing processed is not visible from the time when it enters theprocessing unit until it emerges therefrom, fully developed.Particularly where the paper is to be utilized in conjunction with anoscillographic recording, it is desirable that the recording be visibleas soon as is feasible.

It is an object of this invention to provide a processor forphotographic paper of the above type which is so constructed andarranged that the sensitized surface of the paper is visible throughoutits travel through the processing apparatus.

A further object is to provide such a processing apparatus which is ofrelatively simple construction and yet which is extremely effective forthe intended purpose.

Further objects will become apparent from the following description andclaims particularly when considered in the light of the accompanyingdrawing wherein:

FIG. 1 is a top plan view of one embodiment of my improved processorwith a strip of paper to be processed thereon shown in phantom lines.

FIG. 2 is a longitudinal sectional view of the processor.

FIG. 3 is a fragmentary cross sectional view taken on the line 3-3 ofFIG. 1.

FIG. 4 is a somewhat diagrammatic view showing the manner in which theprocessor might be associated with an oscillograph recording apparatus.

FIG. 5 is a front view of a slightly modified embodiment of myinvention.

As best shown in FIGS. 1 and 2, my improved processing apparatuscomprises a metal block or shoe 1 across the upper surface 2 of which astrip 3 of heat developable photographic paper is adapted to be drawn,emulsion-side up, as indicated by the arrow 4. As shown in the drawing,the upper surface 2 of block 1 is preferably convexly curved so as tofacilitate maintaining close contact between the strip and the blockthroughout its travel thereacross. The block 1 is arranged to be heated3,177,793 Patented Apr. 13, 1965 so that its surface 2 will be at atemperature somewhat above the boiling point of water, say from 225 F.to 400 F. To this end, electric heating elements 5, adapted to beconnected to a suitable source of current (not shown), may be providedin an appropriate recess 6 formed in the upper surface of a plate 7suitably secured to the under surface 8 of block 1.

The surface 2 across which the strip of paper 3 is to be drawn, isprovided with a pair of laterally spaced, parallel, guiding surfaces 9and 10 which are adapted to be in intimate face-to-face contact with theedge portions of the strip throughout its movement across block 1. It isunderstood, of course, that the above-mentioned edge portions of thestrip 3 would not normally be exposed and that only those portions ofthe web between the guide surfaces 9 and It? would require developing.The surface of the block 1 between these guide surfaces 9 and 1% may beconsidered as being divided into two zones, a preconditioning zone A,and a processing zone B. As will later appear, the paper moving acrossblock 1 will be moistened somewhat in the preconditioning zone A whileactual development of the latent image thereon will be produced while itis traversing zone B.

Considering first zone A, the surface of block 1 between the guidingsurfaces 9 and 10 is depressed somewhat below these guiding surfaces soas to form a relatively large, shallow recess 11 extending throughoutthe length and width of the preconditioning zone A. Therefore,throughout this preconditioning zone, only the unexposed, lateral edgesof the strip of paper 3 will be in actual contact with the surface ofblock 1.

The surface 2 of block 1 in the processing zone B is formed to provide aplurality of spaced depressions or pockets 12 with intervening walls 13,the outermost surfaces 14 of the walls 13 being coplanar with theguiding surfaces 9 and 10. Suitable shallow slots or grooves 15 areprovided in the walls 13 so as to provide fluid communication betweenthe various pockets and between the pockets and the recess 11 of zone Abelow the plane of the guide surfaces 9 and 10. While, in the drawing,we have shown the pockets 12 in the form of parallel, transverse groovesextending over the entire width of the processing area, this is merelyone example of the many possible configurations which could be employed.The primary requirement is to provide, along any straight line extendinglengthwise of the path of movement of the strip, an alternating seriesof raised 14 and depressed areas 12 with the depressed areas or pockets12 in fluid communication with one another and with the recessed area11. As best shown in FIG. 1 it is preferable that the interconnectinggrooves 15 be located in a random, nonrepeating, non-symmetricalarrangement thereby avoiding any tendency to cause streaking of thedeveloped image.

It will be noted in FIGS. 1 and 2 that the grooved portion of theprocessing zone B does not extend clear to the right-hand end of theblock 1. To avoid the necessity of supplying a separate source ofmoisture, applicant utilizes the moisture driven from the portion of thepaper in zone B to dampen that portion of the paper traveling throughzone A. It is for this reason that the pockets or depressions 1-2 andthe interconnecting grooves 15 are provided. In operation, moisture isdriven out of the paper as it is heated by contact with the surf-aces1-4 in zone B and tends to collect as vapor in the pockets 12 buildingup a slight pressure therein. Thus the vapor driven into pockets 12 willbe forced to travel through the slots 15 into the preconditioningchamber 11 where, due to the fact that the strip is still relativelycool at this point, the vapor will be condensed onto the surface thereofand absorbed thereby. It is 9 found that substantially all of themoisture which can thus be driven out of the paper will have beenremoved therefrom by the time that the paper has reached the last grooveor pocket 12. The last wall 13' therefore forms, in effect, a vaporbarrier, preventing passage of vapor to the right beyond this point andtherefore of fectively limiting the volume into which the vapor canexpand. This insures that the maximum possible amount of vapor will beforced to the left into the preconditioning recess or chamber ll.

It is obvious that my improved processor could be mounted in anydesirable Way. I have shown in FIG. 4, purely as an example, theprocessor mount-ed in conjunction with an o-scillographic recorder 16 sothat the web 3 of exposed paper will be guided by suitable guide rollers17 and 18 so as to pass over the processing block 1 immediately asit isdrawn from the recorder, by a take-up reel 19. With such an arrangementthe recorded information will become visible almost immediately after ithas been recorded. 1

In operationthe web'of exposed paper will be drawn across the processingapparatus at a uniform steady rate, sufficient moisture being present inthe first portion of the strip to precondition succeeding portionsthereof so that they will be developed. In practice it is found that theimage will begin to appear almost as soon as it reaches the leading edgeof the processing zone B, the density of the image increasing as ittraverses the remainder of this zone. Thus the operator may view therecorded information almost immediately and without inconvenience sinceit is always in direct view.

Certain photographic papers of the heat developable type areexceptionally difficult to process without the use of additionalmoisture. Even on an apparatus'such as is described above where thepockets 12 provide space beneath the web for the vapor to collect, somevapor will escape through the paper web if the web is at all porous. Itis therefore highly desirable in the case of such hard-to-develop papersto provide additional means to prevent this loss of available moisture.

In such cases improved devloping action can be 0btained by training aflexible belt 20 around guide rollers 17 and 18 as clearly shown in FIG.so that the belt overlies the surface of the web 3 being processed as ittraverses the shoe 1. To retain the advantage of being able to observethe developed image as soon as it appears, belt 20 is preferably made ofa heat-resistant transparent material such as polyester tape material.The apparent thickness of both the belt 20 and web 3 have necessarilybeen considerably exaggerated in FIG. 5. Operation of the FIG. 5embodiment will be exactly like that previously described except thatthe belt 20 will, of course, bepulled about rollers 17 and 18 by virtueof its frictional engagement with the upper surface of web 3 and willprevent escape of moisture therethrough.

While I have shown but two forms of the invention, it will be obviousfrom the preceding description that many other variations andmodifications could be made without departing from the spirit and scopeof the invention as defined by the appended claims.

I claim:

1. Processing apparatus for a web of heat-developable photographicmaterial comprising a body member of relatively high thermalconductivity having a web-guiding surface across which said web is to bedrawn in a predetermined path in intimate contact therewith, and meansfor supplying heat to said body member, said web guiding surface of saidbody member being provided with a plurality of spaced depressions influid communication with one another and extending over substantiallythe entire width of said surface but terminating short of the lateraledges of said path.

2. Processing apparatus as in claim '1, wherein said web guiding surfaceis further provided with a recess positioned along said path ahead ofsaid depressions and in fluid communication therewith, the dimension ofsaid recess lengthwise of said path being considerably greater than thatof the individual depressions and the width of said recess beingsubstantially coextensive with that of said plurality of depressions.

3. Processing apparatus as in claim 2 wherein said surface is providedwith grooves interconnecting at least certain of said depressions withsaid recess to provide said fluid communication therebetween.

4. Processing apparatus for a strip of heat-devel'opable photographicmaterial comprising a body member providing a guide surface over whichsaid strip is to be moved along a predetermined path and means for heating said body member whereby to apply heat to said strip, said guidesurface being provided with a plurality of depressions in the areatraversed by said path but terminating short of the lateral edges ofsaid path and adapted to form pockets facing the adjacent surface of astrip moving over said guide member, and with grooves interconnecting atleast certain of said pockets.

5. Processing apparatus as in claim 4 wherein one of said depressionswhich is located in that portion of said guide surface which is firsttraversed by paper moving along said path is considerably larger in areathan the others, said one depression extending across substantially theentire width of said path and a substantial distance lengthwise thereof.

6. Processing apparatus as in claim 5 wherein said grooves interconnectsaidone depression with at least those other depressions positionedalong said path immediately following said one depression in thedirection of intended movement of said strip.

7. Processing apparatus for a web of heat-developable photographicmaterial comprising a guide shoe over the surface of which said web isto be moved along a predetermined path, and means for heating said guideshoe, said guide :shoeproviding a preliminary web-conditioning zone atthe beginning of said path and a processing zone following-saidconditioning zone, the surface of said. guide shoe in said conditioningzone being arranged to provide a relatively large, outwardly facingrecess extending substantially across but terminating short of the widthof said path and throughout the entire length of said conditioning zone,and the surface of said guide shoe in said processing zone inwardly ofthe edges of said path being provided with a plurality of spaceddepressions at least some of which are in fluid communication with saidrecess, said depressions having wall portions therebetween so positionedthat every portion of the inner face of a web moving along said path andtraversing said depressions and recess will, during such movementsuccessively between said guiding surfaces providing, sequentiallyarranged along said path, a web preconditioning zone followed by aprocessing zone, the surface of said shoe throughout the length andwidth of said preconditioning zone being depressed below theoplane ofthe adjacent portion of said guiding surfaces to form an outwardlyfacingrecess, and thesurface of said shoe in said processing zone being formedto provide a plurality of raised and depressed areas, alternatelyarranged lengthwise of said path, and the outermost surfaces of saidraised areas being coplanar with the adjacent portions of said guidingsurfaces, said depressed areas and raised areas being so arranged as toconjointly form a network of fluid conducting passageways below theplane of said guiding surfaces and connecting at least certain of saiddepressed areas in said treatment zone with said recess.

9. Processing apparatus for a web of heat-developable photographicmaterial comprising a guide shoe over the surface of which a web to beprocessed is adapted to be moved along a predetermined path, and meansfor heating said guide shoe, said guide shoe providing a pair oflaterally spaced, coplanar, guiding surfaces conjointly defining saidpath of movement and adapted to engage, in intimate face-to-face contacttherewith, the edge portions of a web moving along said path, thesurface of said shoe along said path being formed to provide, insequence, a preconditioning Zone and a processing zone, said shoesurface between said guiding surfaces throughout said preconditioningzone being depressed below the plane of said guiding surfaces to form anoutwardly facing recess, and the shoe surface between said guidingsurfaces in said processing zone being provided with a plurality oftransversely extending grooves having outwardly extending wallstherebetween, the outermost surfaces of which walls are coplanar withsaid guiding surfaces, and with additional grooves provided in at leastcertain of said outwardly extending walls, said additional groovesproviding passageways between the associated first-mentioned grooves andsaid recess.

10, Processing apparatus as in claim 9 wherein the longitudinal extentof said recess is several times greater than the distance lengthwise ofsaid path between corresponding portions of adjacent ones of saidlaterally extending grooves.

11. Processing apparatus as in claim 9 wherein the additional grooves inadjacent ones of said outwardly extending Walls are staggered laterallyof said wall relative to one another.

References (Zited in the file of this patent UNITED STATES PATENTS941,721 Moss Nov. 20, 1909 1,861,329 Uhlich et al May 31, 1932 2,495,053Conaway et a1 J an. 17, 1950 3,0l2,l41 Thomiszer Dec. 5, 1961 3,074,332Robinson Jan. 22, 1963 3,088,324 Jacobs May 7, 1963

1. PROCESSING APPARATUS FOR A WEB OF HEAT-DEVELOPABLE PHOTOGRAPHICMATERIAL COMPRISING A BODY MEMBER OF RELATIVELY HIGH THERMALCONDUCTIVELY HAVING A WEB-GUIDING SURFACE ACROSS WHICH SAID WEB IS TO BEDRAWN IN A PREDETERMINED PATH IN INTIMATE CONTACT THEREWITH, AND MEANSFOR SUPPLYING HEAT TO SAID BODY MEMBER, SAID WEB GUIDING SURFACE OF SAIDBODY MEMBER BEING PROVIDED WITH A PLURALITY OF SPACED DEPRESSIONS INFLUID COMMUNICATION WITH ONE ANOTHER AND EXTENDING OVER SUBSTANTIALLYTHE ENTIRE WIDTH OF SAID SURFACE BUT TERMINATING SHORT OF THE LATERALEDGES OF SAID PATH.